Machines such as axial turbines or compressors have an outer casing that houses an inner casing; the inner casing carries vanes. Within the inner casing a rotor is housed that carries blades.
Blades and vanes must withstand very heavy operating conditions, thus they need periodical checking and controls.
Different methods are known to access the vanes and blades.
For example the upper part of the outer casing and inner casing can be removed and then also the rotor can be removed, in order to access the vanes at the bottom part of the inner casing.
Nevertheless, removing the rotor is very time consuming, thus it is preferably avoided.
It is also known to remove the upper part of, the outer and inner casing, replace the upper part of the inner casing with a ring sector and then provide rollers between the bottom part of the outer and inner casing.
This way the bottom part of the inner casing can be rotated on the rollers, bringing it at the top of the machine, such that it can be removed without removing the rotor.
This method could cause damages between the adjacent parts of the inner and outer casing. For example, this can be caused by the possible relative axial displacement of the inner and outer casing, such that adjacent surfaces of the inner and outer casing that normally are separated by a gap come into contact.